Method of leveling cellular concrete



July 30, 1935. K. P. BILLNER.

METHOD 0? LEVELING CELLULAR CONCRETE Filed June 27, 1955 INVENTOR. w' I?49% mation therein of a great number of small air or gas filled cells,as a result of which the Patented July 30, 1935 METHOD OF LEVELINGCELLULAR CONCRETE Karl P. Billner, New

York, N. Y., assignor to The Aerocrcte Corporation of America, New York,N. Y., a corporation of Delaware Application June 27, 1933, Serial No.677,858

1 Claim.

My invention relates to an improved method of leveling cellular concreteor in other words of producing Cellular a level top surface for thesame. concrete is characterized by the forterial is light, sound-proofand fireproof. The cells in question may be formed chemically by the useof a water dissociating powder like aluminum as disclosed in U. S.Patent 1,087,098 to Aylsworth soap foam and Dyer or physically by the sothe admixture of or in any other. suitable way.

The aerated nature of the material makes it possible to compress the topsurface before the cellular concrete has set, thereby obtaining a densecompressed upper layer in the material, having but few gas or airbubbles therein. Such bubbles as remain are of reduced size, owing tothe compression applied thereto.

Heretofore, the attempt has been made to secure a dense. upper layer ofthe material by pressing upon the top surface thereof, as by darbying itwith a board. In practice this is not a satisfactory operation since thematerial tends to stick to the board and therefore the upper surfacebecomes uneven. As a result it has been found necessary to apply somekind of a filling coat if an even surface is required.

My improved method consists in applying pressure to the top surface ofthe cellular concrete by means of a roller similar to an ordinary gardenroller.

Such a roller not only applies a very heavy pressure to the cellularconcrete but also results in the formation of a smooth upper surfacetherein. By merely darbying the material but little pressure is appliedso that the upper portion of the mass is not nearly so dense as when aroller is used. Furthermore as I have pointed out; a much more levelsurface is obtained by the use of a roller than can be secured bydarbying.

In carrying my invention the cellular concrete in suitable forms of sizeresult in the desired slab. The amount shape to of cellular cause theslightly higher than into effect I first pour and concrete thus pouredis sufficient to top surface after expansion to rise the desired toplevel of the finished slab. Screeds are set at a convenient distanceapart so that the tops of the screeds are in the the slab.

same plane as After the aeration of the concrete has been completedthe'concre or substantially so and at least before te has obtained itsfinal set and is still the finished surface of plastic the roller isrolled over the concrete resting upon the screeds above mentioned. Thisoperation results in a compression of the upper portion of the cellularconcrete, by causing the gas or air bubbles therein near the surface tobe compressed in size, and at the same time much of the gas orair iromthe cells adjacent the surface will escape therefrom. The resulting slabwhen it becomes hard will beformed with a dense upper portionsubstantially free from the gas or air cells and at the same time theupper surface will be smooth and level.

Preferably the roller is covered with a flexible sheet such as cloth orrubber fitted loosely thereto. In operation the loose fitting sheetforms a 15 sag at the back and the sheet therefore adheres to thecompressed surface behind the advancing roller. The portion of the sheetbehind the roller will therefore be successively ripped off from thesurface of the compressed concrete in the operation. In this way thereis less tendency of portions of the upper surface to be removed than ifa plane roller were used or if the flexible sheet were tightly applied.

Ifind furthermore that it is possible to secure a perfect surfacewithout any sticking of the material to the roller if suitable provisionis made to keep the roller well greased with oil or lubricated withwater during its operation.

In order that my invention maybe better understood attention is directedto the accompanying drawing forming a part hereof and in which Figure lis a longitudinal view showing the concrete in process of beinglevelled.

Figure 2, a transverse sectional view on the line 2-2 of Figure 1, and vFigure 3, a transverse sectional viewon the line 3-3 of Figure 1.

In these views like parts are represented by the same numerals.

The form or mold in which the concrete is poured is provided with sidesl.-|.' Within this mold is poured a mass 2 of cellular concrete whichupon expanding as shown in Figure 3 rises somewhat above the sides. Aroller 3 supported by 45 the sides I rolls the concrete down from thelevel of Figure 3 to that of Figure 2 This roller is covered by a sheetof cloth"! sufliciently loose to form aloop behind the roller 3 as itmoves from rightto left in Figure 1.

Having now described my invention what I claim is newtherein and desireto secure by Letters Patent isas follows: e I The method of producingslabs of cellular con-- crete which consists in permitting a ma s offace thereon and simultaneously with the application of such rollingpressure and in the rear of the area of application thereof, incontinuously performing a ripping action on the compressed material,substantially as set forth.

KARL P. BILLNER.

